Korean J Ophthalmol.  2012 Apr;26(2):104-110. 10.3341/kjo.2012.26.2.104.

The Effect of Various Factors on Variability of Retinal Nerve Fiber Layer Thickness Measurements Using Optical Coherence Tomography

• Youm DJ
• Kim H
• Shim SH
• Jang HJ
• Kim JM
• Park KH
• Choi CY
• Cho JG

• KMID: 1364863
• DOI: http://doi.org/10.3341/kjo.2012.26.2.104

Abstract

PURPOSE
To evaluate the effects of various factors on the variability of retinal nerve fiber layer (RNFL) thickness measurements using the Stratus optical coherence tomography (OCT) in normal and glaucomatous eyes.
METHODS
Four hundred seventy-four subjects (103 normal eyes and 371 glaucomatous eyes) were scanned to determine the RNFL thickness measurements using the Stratus OCT. Measurements were obtained twice during the same day. The standard deviation (SD) was used to compare the variability in RNFL thickness measurements of the normal subjects to that of the glaucomatous patients. Multivariate regression analysis was used to evaluate which covariates were independent predictors of SD in overall mean RNFL thickness.
RESULTS
The mean SD of all RNFL thickness measurements was larger in the glaucoma group except in one sector. In the multivariate regression analysis, the average signal strength (SS) and the relative SS change (difference in SS between initial and repeat scans, divided by initial SS) were independent predictors of the SD in the RNFL thickness measurements (partial R2 = 0.018, 0.013; p = 0.016, 0.040, respectively).
CONCLUSIONS
Glaucomatous eyes tend to be more variable than normal eyes in RNFL thickness measurement using the Straus OCT. The average SS and the relative SS changes appear to correlate with the variability in RNFL thickness measurement. Therefore, the results of the RNFL analysis should not be interpreted independently of these factors.

Keyword

Glaucoma; Optical coherence tomography; Retinal nerve fiber layer thickness; Variability

MeSH Terms

Aged
Female
Glaucoma/*pathology
Humans
Male
Middle Aged
Multivariate Analysis
Nerve Fibers/*pathology
Predictive Value of Tests
Reference Values
Regression Analysis
Reproducibility of Results
Retina/*cytology/*pathology
Tomography, Optical Coherence/*methods/*standards

Figure

• 

  Fig. 1 The standard deviation (SD) of 406 overall mean retinal nerve fiber layer (RNFL) thickness measurements plotted against various factors for all subjects.

Reference

1. Quigley HA, Katz J, Derick RJ, et al. An evaluation of optic disc and nerve fiber layer examinations in monitoring progression of early glaucoma damage. Ophthalmology. 1992. 99:19–28.

2. Yucel YH, Gupta N, Kalichman MW, et al. Relationship of optic disc topography to optic nerve fiber number in glaucoma. Arch Ophthalmol. 1998. 116:493–497.

3. Leung CK, Chan WM, Yung WH, et al. Comparison of macular and peripapillary measurements for the detection of glaucoma: an optical coherence tomography study. Ophthalmology. 2005. 112:391–400.

4. Hoffmann EM, Medeiros FA, Sample PA, et al. Relationship between patterns of visual field loss and retinal nerve fiber layer thickness measurements. Am J Ophthalmol. 2006. 141:463–471.

5. Medeiros FA, Zangwill LM, Bowd C, Weinreb RN. Comparison of the GDx VCC scanning laser polarimeter, HRT II confocal scanning laser ophthalmoscope, and stratus OCT optical coherence tomograph for the detection of glaucoma. Arch Ophthalmol. 2004. 122:827–837.

6. Quigley HA, Addicks EM, Green WR. Optic nerve damage in human glaucoma: III. Quantitative correlation of nerve fiber loss and visual field defect in glaucoma, ischemic neuropathy, papilledema, and toxic neuropathy. Arch Ophthalmol. 1982. 100:135–146.

7. Mikelberg FS, Yidegiligne HM, Schulzer M. Optic nerve axon count and axon diameter in patients with ocular hypertension and normal visual fields. Ophthalmology. 1995. 102:342–348.

8. Huang D, Swanson EA, Lin CP, et al. Optical coherence tomography. Science. 1991. 254:1178–1181.

9. Budenz DL, Chang RT, Huang X, et al. Reproducibility of retinal nerve fiber thickness measurements using the stratus OCT in normal and glaucomatous eyes. Invest Ophthalmol Vis Sci. 2005. 46:2440–2443.

10. Budenz DL, Fredette MJ, Feuer WJ, Anderson DR. Reproducibility of peripapillary retinal nerve fiber thickness measurements with stratus OCT in glaucomatous eyes. Ophthalmology. 2008. 115:661–666e4.

11. Paunescu LA, Schuman JS, Price LL, et al. Reproducibility of nerve fiber thickness, macular thickness, and optic nerve head measurements using Stratus OCT. Invest Ophthalmol Vis Sci. 2004. 45:1716–1724.

12. Carpineto P, Ciancaglini M, Aharrh-Gnama A, et al. Custom measurement of retinal nerve fiber layer thickness using Stratus OCT in normal eyes. Eur J Ophthalmol. 2005. 15:360–366.

13. Bland JM, Altman DG. Measurement error and correlation coefficients. BMJ. 1996. 313:41–42.

14. Suzuki Y, Iwase A, Araie M, et al. Risk factors for open-angle glaucoma in a Japanese population: the Tajimi Study. Ophthalmology. 2006. 113:1613–1617.

15. Tzamalis A, Kynigopoulos M, Schlote T, Haefliger I. Improved reproducibility of retinal nerve fiber layer thickness measurements with the repeat-scan protocol using the Stratus OCT in normal and glaucomatous eyes. Graefes Arch Clin Exp Ophthalmol. 2009. 247:245–252.

16. Gurses-Ozden R, Ishikawa H, Hoh ST, et al. Increasing sampling density improves reproducibility of optical coherence tomography measurements. J Glaucoma. 1999. 8:238–241.

17. Blumenthal EZ, Williams JM, Weinreb RN, et al. Reproducibility of nerve fiber layer thickness measurements by use of optical coherence tomography. Ophthalmology. 2000. 107:2278–2282.

18. El-Ashry M, Appaswamy S, Deokule S, Pagliarini S. The effect of phacoemulsification cataract surgery on the measurement of retinal nerve fiber layer thickness using optical coherence tomography. Curr Eye Res. 2006. 31:409–413.

19. Savini G, Zanini M, Barboni P. Influence of pupil size and cataract on retinal nerve fiber layer thickness measurements by Stratus OCT. J Glaucoma. 2006. 15:336–340.

20. Stein DM, Wollstein G, Ishikawa H, et al. Effect of corneal drying on optical coherence tomography. Ophthalmology. 2006. 113:985–991.

21. Youm DJ, Kim JM, Park KH, Choi CY. The effect of soft contact lenses during the measurement of retinal nerve fiber layer thickness using optical coherence tomography. Curr Eye Res. 2009. 34:78–83.

22. Stein DM, Ishikawa H, Hariprasad R, et al. A new quality assessment parameter for optical coherence tomography. Br J Ophthalmol. 2006. 90:186–190.

23. Wu Z, Vazeen M, Varma R, et al. Factors associated with variability in retinal nerve fiber layer thickness measurements obtained by optical coherence tomography. Ophthalmology. 2007. 114:1505–1512.